CVE-2026-43348 (GCVE-0-2026-43348)
Vulnerability from cvelistv5
Published
2026-05-08 13:41
Modified
2026-06-14 17:44
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER When registering VTL0 memory via MSHV_ADD_VTL0_MEMORY, the kernel computes pgmap->vmemmap_shift as the number of trailing zeros in the OR of start_pfn and last_pfn, intending to use the largest compound page order both endpoints are aligned to. However, this value is not clamped to MAX_FOLIO_ORDER, so a sufficiently aligned range (e.g. physical range [0x800000000000, 0x800080000000), corresponding to start_pfn=0x800000000 with 35 trailing zeros) can produce a shift larger than what memremap_pages() accepts, triggering a WARN and returning -EINVAL: WARNING: ... memremap_pages+0x512/0x650 requested folio size unsupported The MAX_FOLIO_ORDER check was added by commit 646b67d57589 ("mm/memremap: reject unreasonable folio/compound page sizes in memremap_pages()"). Fix this by clamping vmemmap_shift to MAX_FOLIO_ORDER so we always request the largest order the kernel supports, in those cases, rather than an out-of-range value. Also fix the error path to propagate the actual error code from devm_memremap_pages() instead of hard-coding -EFAULT, which was masking the real -EINVAL return.
References
Impacted products
Vendor Product Version
Linux Linux Version: 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f
Version: 7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/hv/mshv_vtl_main.c",
            "include/uapi/linux/mshv.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a142ca4b6481e71498712800b20e0c0fcf02843b",
              "status": "affected",
              "version": "7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f",
              "versionType": "git"
            },
            {
              "lessThan": "404cd6bffe17e25e0f94ed2775ffdd6cd10ac3fd",
              "status": "affected",
              "version": "7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/hv/mshv_vtl_main.c",
            "include/uapi/linux/mshv.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.2",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER\n\nWhen registering VTL0 memory via MSHV_ADD_VTL0_MEMORY, the kernel\ncomputes pgmap-\u003evmemmap_shift as the number of trailing zeros in the\nOR of start_pfn and last_pfn, intending to use the largest compound\npage order both endpoints are aligned to.\n\nHowever, this value is not clamped to MAX_FOLIO_ORDER, so a\nsufficiently aligned range (e.g. physical range\n[0x800000000000, 0x800080000000), corresponding to start_pfn=0x800000000\nwith 35 trailing zeros) can produce a shift larger than what\nmemremap_pages() accepts, triggering a WARN and returning -EINVAL:\n\n  WARNING: ... memremap_pages+0x512/0x650\n  requested folio size unsupported\n\nThe MAX_FOLIO_ORDER check was added by\ncommit 646b67d57589 (\"mm/memremap: reject unreasonable folio/compound\npage sizes in memremap_pages()\").\n\nFix this by clamping vmemmap_shift to MAX_FOLIO_ORDER so we always\nrequest the largest order the kernel supports, in those cases, rather\nthan an out-of-range value.\n\nAlso fix the error path to propagate the actual error code from\ndevm_memremap_pages() instead of hard-coding -EFAULT, which was\nmasking the real -EINVAL return."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:44:59.767Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a142ca4b6481e71498712800b20e0c0fcf02843b"
        },
        {
          "url": "https://git.kernel.org/stable/c/404cd6bffe17e25e0f94ed2775ffdd6cd10ac3fd"
        }
      ],
      "title": "mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43348",
    "datePublished": "2026-05-08T13:41:51.909Z",
    "dateReserved": "2026-05-01T14:12:56.003Z",
    "dateUpdated": "2026-06-14T17:44:59.767Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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